CPU cooler clearance: Why our data sometimes deviates from the case manufacturer’s specs

One of the most recent examples was the new NZXT H2 Flow case where the manufacturer specifies up to 75mm CPU cooler height whereas our measurements have shown that the case provides sufficient clearance for coolers up to 79mm. That’s not only a quite significant deviation, it also means that our NH-L12Sx77 cooler actually fits this case whereas on paper, it shouldn’t. This is precisely why it’s so important to take actual measurements: Based on the manufacturer’s specifications alone, you might have settled with a smaller, less capable cooler.

Similarly, we’ve measured 70.7 instead of the specified 68mm in the Thermaltake TR100 case. While a difference of 2.7mm may not seem like much, having more than 70mm, e.g. enables you to fit our NH-L12 Ghost S1 Edition cooler rather than the smaller NH-L9x65.

With Corsair cases such as the popular 5000D, 4000D and Frame 4000D, we’ve actually measured a full 10mm more clearance than specified. For the Frame 4000D, for example, this means 180 instead of 170mm cooler clearance, which can be decisive if you want to pair an NH-D15 G2 (168mm) with slightly taller RAM modules so you need to move the front fan up a bit.

On the flip side, in other cases, the actual clearance is slightly smaller than specified by the manufacturer, which can lead to even more severe problems, as you may opt for a cooler that may end up pressing against the side panel or not fitting at all. For example, we only measured 168.3mm instead of the specified 170mm in the ASUS Prime AP201. This means that when using an NH-D15 G2, there’s absolutely no room to move the front fan higher up to increase RAM clearance, so you will be limited to standard height 32mm modules.

Another example of a case where we measured less clearance than specified is the recent Lian Li B4-mATX where we measured 164.5 instead of 168mm, which means that unlike the specifications suggest, the NH-D15 G2 does not fit this case.

In order to make this measurement data available to our customers and the community, we have implemented a custom field in the case compatibility database on our website. Whenever you see a small tool-tip icon next to the max. CPU cooler height specification of a particular case model, this means that we have taken our own measurements and saw deviations from the manufacturer’s specifications: